Folding push chair



March 11, 1952 THOMAS 2,588,896

FOLDING PUSH CHAIR Filed April 15. 1949' 2 SHEETS-SHEET l INVENTOI? GEORqE THO/"1A5.

ATTORNEY 11, 1952 G, THOMAS FOLDING PUSH CHAIR Filed April 15. 1949 2 SHEETS-SHEET 2:

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IN VEVNTOR GEORGE THO/1A6.

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Patented Mar. 11, 1952 UNITED STATES PATENT OFFICE FOLDING PUSH CHAIR George Thomas, Hayes, England Application April 15, 1949, Serial No. 87,800

2 Claims.

This invention relates to folding push chairs of the kind comprising a folding back, seat and arms which are adapted to be collapsed into a compact form when the chair is not in use so as to resemble closely an attache or suit case which can be easily carried.

More particularly the present invention is concerned with improvements in a folding push chair wherein the ground wheels of two pairs of ground wheels provided respectively at the front and back of the chair, are each mounted on an axle bracket and the four axle brackets thus provided (two at each side of the chair) are adapted to rotate about upright pivots carried by the end members of a bridge shaped frame extending transversely of the chair so that the wheels can be folded into the frame so as to be parallel to one another and extend in a transverse direction in the folded inoperative positions.

An object of the present invention is to provide an improved and more efficient construction of folding push chair.

According to the present invention there is provided a folding push chair of the kind referred to comprising in combination folding side frame members supporting the chair seat which are interconnected with upright pivots of the axle brackets in such a manner that they automatically impart a turning movement to said upright pivots to swing the axle bracket and wheels into and out of an operative position when the chair is opened out and collapsed respectively and means whereby a wheel of each pair of wheels is arranged to open earlier and close later than the other wheel so as to prevent the wheels of each pair of wheels at the front and the back fouling when opening and closing.

According to one embodiment of the invention I the upright pivots of the axle brackets are fitted to turn with the movement of the blocks to swing the wheel brackets in and out during collapsing and opening of the chair.

one wheel of each pair of wheels at the front and back of the chair is made to close before and open later than the remaining wheel so that the wheels do not foul one another during their movement. In the case of the arrangement employing gear wheels this is effected by fitting the gear wheels on the upright pivots of the axle brackets with dogs which co-act with a bar-like member fitted to the upper end of each upright pivot, the gear wheels being mounted loosely on the upper ends of the pivots so that no movement is transmitted to or permitted by the pivots until the dogs engage with or move away from the bar-like members on the gears, the dogs of one gear at each side of the chair acting on the barlike member of that gear before or after the dogs of the other gear at the same side of the chair act on their associated bar member. The movement of the brackets is controlled by springs which operate to advance and retard the movement of said brackets.

When the upright pivots are formed with helices, the opening and closing of one wheel of a pair of wheels is effected by varying the pitch of the helices so that one has a quick start and the other a slow one.

In order that the invention may be clearly understood and readily carried into effect, reference will now be made to the accompanying drawings which illustrate two embodiments of the invention by way of example. In the drawings:

Figure 1 is a side elevation of the push chair erected.

Figure 2 is a view showing the chair collapsed.

Figure 3 is a front view, drawn to a larger scale of the part of the chair below the seat with the chair open.

Figure 4 is a fragmentary perspective view of the gear mechanism at one side of the chair.

Figure 5 is a detail sectional view of a gear abridge shaped. frame I which extends trans-n versely of the chair and each depending end wall 2 of the frame is formed with lugs 3 for receiving two oppositely directed L shaped axle brackets 4 for the ground wheels at that side of the chair, the vertical limbs 6 of the brackets 4 being pivotally supported by the lugs 3 in the end walls 2 and the outer free ends of the horizontal portions 1 of the brackets receiving the wheels 5.

The upper-end of each of the vertical limbs 6 of the wheelbrackets 4 projects above the top of the end wall 2 of the bridge I and is fitted with a gear wheel or toothed gear segment 8 which is turnable freely on the limb 6. The two gear wheels 8 thus provided at each side of the bridge I (see particularly Figure l) are not in mesh but each is engaged by a gear segment 9 (when-thepush chair is collapsed) provided at the; lower or inner end of normally upwardly and outwardly inclined frame members II] for supporting the seat II, the latter being provided with two such frame (members It at each side of the chair.

The two. gear segments 9 on the seat frame members") at eachside of the chair are preferably-in mesh to ensure that their movement is. co-ordinated and to facilitate folding .of the wheels5;

To prevent the wheels 5 fouling each other when opening or closing, means are provided to m-akeawheel of each pair of wheels open earlier and close later than the other wheel. Such means may comprise two dog-couplingsIZ which are. fitted to each of the gear elements 8 and which have a degree of lost motion before positive engagement with a bar-like part I3 rigidly secured to the upper end of each vertical limb 6 l of the pivoted axle brackets, the lost motion beingicontrolled :by springs I4 each of which is anchored at one end to the bar I3 on the respective axle bracket, and at its other end to the relatively stationary bridge I, two of said springs I4 operating to advance, and another two acting to --retard,'the,movement of the axle brackets 4. Suchan arrangementensures that one pair of wheels is partly opened before the other pair commence to move, and vice-versa.

The sequence'of opening of two wheels 5 ,at one side .of the push chair is illustrated diagrammatically by Figures 6 to 8.

Figure 6 illustrates the axle brackets l of two Wheels in a closed or folded position. Now as the chair is opened and extended the two frames. members") at thatside of the chair are swung upwardly and the gear elements 9 turn the gear, wheels-8. In the foldedinposition the right hand spring .14 as viewed in these figures is under tension so that asthe gear 8 is turned in. a clockwise direction the dogs I2 tend to move away from the associated bar I3 which follows the dogs round as thespring I l re-asserts itself until the axle bracket reaches its extended. position as shown in Figure 7.

Asthisaction is taking place the other gear wheel 8 is, turned by its associated element 9 in the reverse direction and in. this casethe spring I4 isclosed and holdsits bar it and-the associated axle bracket 4 in the closed position untilsuch time'as the dogs I2 on this gear wheel 8 engage and turn the bar I3 and open the axle bracket 7 in the left hand bracket being fully opened out 1 and-the-seat II-cover the two sides respectively as shown in Figure 8 and during opening out of the left hand bracket the dogs I2 of the right hand gear 8 have moved away from the associated bar I3. Thus in reverse action when the wheels 5 are being closed the dogs I2 on the left hand gear 8 move away from their bar and the spring I4 re-asserts itself to close the axle bracket Whereas the dogs I2 of the right hand gear have an idle movement before theyengage their bar to close. the axle bracket against the :influence of the spring I4"which is then tensioned again ready for a subsequent opening operation.

In the modification illustrated by Figures 10 to.12 upward and downward movement of the frame members I0 is transmitted to the wheel brackets -4--by- "a nut or block I5 which is acted upon by a link I6.connected between the block I5 and the member I0. The vertical limb 6 of eaehwheel bracket is in this case made up of a square section :bar which is twisted along its length to form a helix ll of variable pitch. The helices. of the two vertical limbs 6 at eachside; of the chair comprise differing variable pitch :so. that one, has a greaterturning action at the beginning of its motion which lessens; as it pro-r; ceeds while the other has a slower turning action? at'the beginning and increases "as it proceeds. Thus as theqmembers I 0 are swung downwardly; fromtheir positions in Figure 10 to the positions. shown in Figure 12 the blocks I5, act so that one, turns. and folds an axle bracket ,in quickly. and: the other folds its axle bracket in slowly. The: gears 9 ,ontherframe members :IIl are preferably retained to ensure the members move in tsyne. chronism.

In both embodiments it is to Jbeappreciated that the movementof the wheels 5 onthe other side is complementary, i. e. onefront wheel moves. inwards to a collapsed position followed :bythe; other front ,wheel,'the latter openingfirst' when the chair is opened out. The two rear wheels: operate similarly.

The present invention also provides improved means for locking the ground wheels 5 inthe:

. open and operative position. Such meanscone.

sists of a footrestIB mounted on a substantially; rectangular frame I9 .which'is pivoted between its: ends-at 20 to thelower. ends of. the side 'mem'-.. bers 2 of the bridgemember I. Whenthe-chair:

is. collapsed this: footrest I 8:.and its frame I9 is-,1

located. vertically withinlthe, bridge shaped. frame;

front wheels 5 and. a partrearwardly behindthe bridge .shaped 1 member and. between .therear;

wheels 5.

Upon theseforwardly and rearwardlydirected: parts of the. footrest frameare fittedhooki-shaped members 12I (see Figure 9)..adapted to engage; the horizontal portions: I of. the axle'brackets so that these brackets with the wheels 5 :are held positively in position duringthe wheeling of the chair. The footrest: frame I I9 is 'also fitted with cam members-22 which act to guide :the members" I "into the hooks2l. As the footrestpivotsatmfi the rear hooks open upwards andthe frontones" downwards.

Figure2 shows the chair in its collapsed posia; tion in rwhich-it canbecarried about-like anattache case. It willbe noted that the back-'23 and a slot in the bottom part of the back material registers with a handle 24 on the bridge member I so that this handle 24 can be engaged when carrying the collapsed chair around.

I claim:

1. The combination in a collapsible push chair of a bridge shaped frame, depending end walls thereon, axle brackets having vertical and horizontal limbs, a pair of wheels mounted on each horizontal limb, pivoted supports for the vertical limbs on said end walls, folding side frame members, a seat supported by the frame members, gear segments on said frame members, gear elements turnable freely on the vertical limbs engaging the gear segments to impart a turning movement to the axle brackets to swing these and the wheels into and out of operative position when the chair is opened out and collapsed respectively, a lost motion device consisting of dog couplings fitted to each of the gear elements 20 1,123,908

and a bar-like part rigidly secured to the upper end of each vertical limb, springs controlling said lost motion device, whereby a wheel of each pair of wheels opens earlier and closes later than the other wheel.

2. In the combination according to claim 1, a footrest device and means thereon for locking the ground wheels in the open and operative position.

GEORGE THOMAS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,048,495 Cleveland Dec. 31, 1912 1,122,517 Lloyd Dec. 29, 1914 McGill Jan. 5, 1915 

